Leadership Update

It has been nearly a year since our last Newsletter, which is partly because we initiated Monthly Updates of recent publications, data products and related information (e.g. media attention, meetings, job announcements), and will continue to do so. Nonetheless, the Newsletter is useful for stepping back and reflecting on what we’ve accomplished over a longer timeframe. For example, since our Science Team Meeting in San Diego this past January, some 28 peer-reviewed ABoVE publications have come out, including 6 papers in the ABoVE Focus Collection of Environmental Research Letters (which now includes over 100 papers). In addition, there were 11 new data sets archived at the ORNL DAAC in the last year, and substantial progress on various synthesis activities advanced by ABoVE thematic working groups (most of which meet on a monthly basis). We also arranged 2 webinars held as part of our regional webinar speaker series (one NWT-focused, and one AK-focused) and, of course, had a big turnout at last December’s annual AGU meeting, with 40 presentations in 4 oral sessions coupled with dozens of eLightning and poster presentations. We have a similar number of presentations and posters lined up in our session this year (see this link for the first of 7 time slots), convened by Liz Hoy, Abhishek Chatterjee, Nancy French, Michelle Mack, and Jonathan Wang. We are pleased to see the sustained interest in these sessions, which are among the largest of the meeting across all disciplines. Moreover, we conducted coordinated field and airborne campaigns again this past summer (more details can be found in this newsletter) and also coordinated with two SnowEx campaigns in April and October (see the ABoVE SnowEx site for details, including lots of great photos).

In leadership team news, Hank Margolis, the Terrestrial Ecology Program Manager responsible for ABoVE, has announced his intention to retire at the end of calendar year 2023 after more than 8 years on the job. NASA Headquarters is in the process of recruiting his replacement. We thank Hank for his leadership and guidance for ABoVE, and wish him the very best in his retirement.

We appreciate what each of you contribute to our collective effort to better understand the vulnerability and resilience of northern ecosystems, from field studies to terrestrial biosphere models. We look forward to seeing many of you in San Francisco for the AGU meeting, hope to see you online at one of our webinar series or working group meetings, and then at ASTM10 in Boulder, 21-24 May 2024.. We are now a year into Phase-3 and the results indicate another banner year lies ahead for ABoVE research! Please be in touch if we can help in any way, and remember we are always open to suggestions for how we can do our part better.

- Scott, Chip, Peter, Libby, Liz, Dan, and Hank

The Passing of Jason Edwards

It is with great sadness that we write to let the ABoVE Team know of the sudden passing of our Canadian Forest Service colleague, Jason Edwards, who was part of CFS and the Northern Forestry Centre in various ways over the past 20 years. Jason was the CFS liaison to ABoVE and attended many of our Science Team meetings to report on the research efforts of these organizations and ways to help link our mutual efforts. He was a friend and colleague to many of us and will be greatly missed. If you would like to find out about efforts to honor Jason and to support his family at this difficult time, contact catherine.mcnalty@NRCan-RNCan.gc.ca

Publication Highlights

ABoVE research continues to move apace, with 28 peer-reviewed publications to date this year, including ones in Nature Climate Change, Global Change Biology, Biogeosciences, and Environmental Research Letters, several of which we highlight here. Are your pubs up to date? We strongly encourage everyone to both peruse and report their project publications to the ABoVE website.

• Clark et al. (2023), examined the spatial relationships of CH4 hotspots for 118 beaver ponds in Alaska using AVIRIS-NG data. The enhancement in hotspots adjacent to beaver ponds is an example of a new disturbance regime that is accelerating the effects of climate change in the Arctic.
• Potter et al. (2023) developed a new burned-area detection algorithm for the period 2001–2019 across Alaska and Canada at 500 m resolution that utilizes finer-scale 30 m Landsat imagery to account for land cover unsuitable for burning. Using this new burned-area product, they developed statistical models to predict burn depth and carbon combustion for the ABoVE Study Area, finding that larger-fire years and later-season burning were associated with greater mean combustion.
• Watts et al. (2023) estimated recent (2003–2015) vegetation net ecosystem CO2 exchange (NEE; Reco − GPP), and terrestrial methane (CH4) emissions for the entire Arctic- boreal zone using a satellite data-driven process- model for northern ecosystems and evaluated using measurements from >60 tower eddy covariance (EC) sites. Accounting for additional emissions from open water aquatic bodies and from fire, using available estimates from the literature, reduced the total regional NEE sink by 21% and shifted many far northern tundra landscapes, and some boreal forests, to a net carbon source. This assessment, based on in situ observations and models, improves our understanding of the high- latitude carbon status and also indicates a continued need for integrated site-to-regional assessments to monitor the vulnerability of these ecosystems to climate change.
• Massey et al. (2023) mapped Landsat per-pixel continuous tree cover and deciduous:evergreen fractional composition across all of boreal North America for the period 2000-2015 (1992 to 2015 across Canada) in 5 year integrated epochs. They used these data sets, which are available at the ORNL DAAC, together with MODIS blue-sky albedo products to calculate radiative forcing feedbacks to climate. Despite extensive fire disturbance that locally increased deciduous vegetation, they found these changes were offset by the gradual increase in coniferous forests in areas that had not recently burned. Overall, there was no net shift toward greater deciduous cover and the albedo feedbacks were also relatively small in net, despite large spatial variability. Future work will extend this analysis to account for the severe fires of more recent years.
• Huemmrich et al. (2023) resampled NDVI at 1 m intervals along a 100 m transect near Utqiagvik, AK that had been previously measured through the 2000–2002 growing seasons. This transect is located in a region with a clear greening trend in MODIS NDVI over the same period.Along the transect they found that multidecadal NDVI change was spatially variable with nearly half of the transect showing greening, about a third not showing conclusive change, and about 20% browning. Most greening occurred in locally lower and wetter areas and was associated with increased green leaf area index. Browning was not related to change in species cover and appeared to be due to increased coverage of standing dead material in graminoid dominated canopies. These types of detailed observations provide insights into the interpretation of satellite based NDVI trends and emphasize the importance of microtopography and surface hydrology in mediating vegetation change in a warming Arctic. The minimal change they observed in plant functional types suggests at this site climate induced changes are reversible and not near an ecological tipping point.

The 2023 ABoVE Airborne Campaign returns to Alaska and Canada

NASA’s Terrestrial Ecology Arctic Boreal Vulnerability Experiment (ABoVE) team executed its fifth airborne campaign during July-August 2023. The team acquired hyperspectral imagery from the AVIRIS-3 instrument. These acquisitions were guided by the requirements of the ABoVE Phase 3 investigations and requests from ABoVE partners in the U.S. and Canada. The new data complement that collected during the ABoVE airborne campaigns executed in 2017, 2018, 2019, and 2022. The Dynamic Aviation B-200 aircraft N53W was based in Fairbanks, AK. About 80% of the areas of interest near Fairbanks and north to Deadhorse were collected. The NGEE-Arctic sites on the Seward Peninsula were collected, and sites near Kotzebue, Noatak, and Atqasuk were completed. Good weather forecast for Utqiagvik led the team to try overnighting there but the aircraft developed mechanical problems which led to a week of down time for repairs, after which the weather failed to cooperate. Favorable conditions in southern Yukon allowed science flights to Whitehorse and points south to Skagway, AK. Extraordinary wildfires in Canada prevented planned sorties in northern Yukon and in the Northwest Territories.

N53W in Fairbanks (photos from Mike Eastwood)

Left to right:
Luis Rios (instrument operator)
Robin Larsen (pilot)
Kait King (pilot)
Mike Eastwood (Instrument lead)

ABoVE Logistics Support Update

ABoVE Science Team Meeting in 2024

ABoVE Internship Updates

Since 2015 ABoVE has sponsored summer internships either in-person at Goddard Space Flight Center, or virtually, to provide training and research opportunities in Arctic science and remote sensing. Students complete projects designed to meet the science goals and objectives of ABoVE, and which foster collaboration and engagement with team members, local communities, and decision-makers within the study domain.

(Rolling acceptance. Applicants must be a current or rising senior or graduate student, U.S. citizen, and have a GPA of 3.0 or greater.)

Many former interns have been able to present their research at conferences and are working to publish in scientific journals as co-authors. Learn more about ABoVE internships here. Some recent intern updates include:

• First-authored publication by intern Elsa Yoseph (see NASA news release here):
  Yoseph, E., Hoy, E., Elder, C. D., Ludwig, S. M., Thompson, D. R., Miller, C. E. 2023. Tundra fire increases the likelihood of methane hotspot formation in the Yukon-Kuskokwim Delta, Alaska, USA. Environmental Research Letters. 18(10), 104042. doi: 10.1088/1748-9326/acf50b
• Dataset publication with intern Seamore (Xiaoran) Zhu, with work by Dong Chen and the Disturbance Working Group:
  Chen, D., X. Zhu, M. Kogure, E.E. Hoy, X. Xu, N.H.F. French, L.T. Berner, A.L. Breen, S. Bret-Harte, S.J. Davidson, J.J. Ebersole, G.V. Frost, S.J. Goetz, R.E. Hewitt, J.K.Y. Hung, C.M. Iversen, G. Iwahana, R. Jandt, L.K. Jenkins, A.N. Kade, I. Klupar, T.V. Loboda, S. Ludwig, M.J. Macander, M.C. Mack, C.R. Meyers, R.J. Michaelides, E.A. Miller, S. Natali, T.W. Nawrocki, P.R. Nelson, A.D. Parsekian, E. Rastetter, M.K. Raynolds, A.V. Rocha, K. Schaefer, U. Schickhoff, E.A.G. Schuur, S. Tsuyuzaki, C.E. Tweedie, S.V. Zesati, D.A. Walker, P.J. Webber, M. Williams, and D. Zona. 2023. Field Data on Soils, Vegetation, and Fire History for Alaska Tundra Sites, 1972-2020. ORNL DAAC, Oak Ridge, Tennessee, USA. DOI: 10.3334/ORNLDAAC/2177

Upcoming AGU Fall Meeting Presentations by former interns including Leah Clayton and Miles Moore.

Early Career Spotlight

Dong (Tony) Chen is an Associate Research Professor at the Department of Geographical Sciences, University of Maryland, College Park. His research primarily focuses on understanding the various impacts of wildfires in the northern ecosystems (i.e., boreal forests and tundra) based on remote sensing and field data. Recently, he has led a project to establish a modeling framework to estimate wildfire-emitted PM2.5 concentrations at the daily interval for the vast northern areas. The output from this project offers direct and quantitative evidence that wildfire is the dominant driver of PM2.5 concentration dynamics in northern lands during the fire season. Dong’s research interest also involves improving the accuracy of remote sensing in mapping northern wildfires. He has led a series of efforts looking into the applications of commonly used burn severity indices including the differenced Normalized Burn Ratio (dNBR). He is currently leading a project to create an Arctic-specific burned area data called the Arctic Boreal Burned Area (ABBA) product. In addition to conducting research, Dong is actively involved in various ABoVE-related activities. He is the lead of ABoVE’s Disturbance Working Group. In this position, he has been curating a monthly webinar series where authors of relevant publications present their recent work. He has also led a tundra synthesis activity which yielded a compiled dataset that contains field data collected in Alaskan tundra over the past half century. A full list of his publications can be found here.

Ludda Ludwig is a PhD candidate in the Earth and Environmental Science department at Columbia University. Her interests are in scaling methane and carbon dioxide emissions, climate change impacts on high-latitude carbon cycling through wildfires and permafrost thaw, and coupled biogeochemical cycling at terrestrial-aquatic interfaces. She uses a blend of research tools including fieldwork measurements, remote sensing, and machine learning, and generally loves finding new ways to apply statistics to research questions. Some examples of her PhD work include investigating wildfire effects on biogeochemical and watershed drivers of inland aquatic CO2 and CH4 and improving bottom-up scaling for waterbody CO2 and CH4 fluxes to the atmosphere. Her most recent PhD work is a preprint on developing an approach to un-mixing eddy covariance fluxes of CO2 and CH4 from heterogeneous tundra, including a comparison using different underlying landcover maps, improved performance with gap-filling, and consequences for scaling up to regional carbon budgets. A full list of her publications can be found here.

Rebecca Scholten is an ABoVE-affiliated PhD candidate at Vrije Universiteit Amsterdam in the Netherlands, exploring the dynamic relationship between arctic-boreal fires and climate warming. Her research combines field data and satellite imagery to understand shifts in high-latitude fire patterns, placing a special emphasis on extreme fire events. This recent research has pointed to the influence of early snowmelt and an anomalous Arctic front jet on the high temperatures and dry conditions seen during recent extreme fire seasons in Siberia. During her PhD she took part in multiple field campaigns gathering unique data on carbon emissions from boreal forest and tundra fires in Siberia, Canada and Alaska. Some of her research has explored the impact of overwintering fires in boreal forests. Prior to her PhD work, she conducted research on ecosystem disturbances and environmental challenges in temperate regions at Scion Research Institute in New Zealand and the Joint Research Center in Italy. A full list of her publications can be found here.

Peter Griffith: Diving Into Carbon Cycle Science

Dr. Peter Griffith is featured in the People of Goddard series.

ABoVE Jobs

Multiple job openings with ABoVE Projects. Here are two highlights:

Faculty Cluster Hire at Northern Arizona University
Northern Arizona University is initiating a cluster hire of multiple faculty positions (including tenure-track and research-track positions, see below) to build on NAU’s existing multidisciplinary strengths in remote sensing analysis that are critical components of many of its outstanding educational and research programs. The goal of this initiative is to increase NAU’s strength in the areas of instrument and application development to advance new techniques and instruments that address timely and critically important scientific questions across disciplines. Successful candidates will help to build remote-sensing capacity in existing areas of strength at NAU in engineering and the natural & social sciences, and/or will help to build new opportunities in novel disciplines. This cluster hire will enable NAU to expand its training and research experiences for undergraduate and graduate students and drive new and existing course offerings. Further, this cluster hire will promote career readiness with a range of in-demand technical skills for both undergraduate and graduate students while fostering a dynamic, multidisciplinary, and collaborative research environment. Specific areas of interest include:

• Space-based remote sensing of Earth and other planetary bodies.
• Terrestrial, near-surface remote sensing (e.g., UAVs, tower- or tripod-mounted devices, hand-held instruments, wearable devices).
• Software & analysis methods (e.g., autonomous devices, machine learning & AI applied to remote devices).
• Instrument design and testing, including integration of off-the-shelf components for novel applications.
• Other areas of remote sensing instrument/application develop that accomplishes over-arching goals described above.

Postdoctoral Scholar
The Postdoctoral Scholar position supports research and development in the Global Earth Observation and Dynamics of Ecosystems (GEODE) Lab in the School of Informatics, Computing, and Cyber Systems (SICCS) at Northern Arizona University’s Flagstaff campus. The Postdoctoral Scholar will work on projects focused on mapping, monitoring and modeling broad scale ecosystem changes, incorporating climate, land use and disturbance. The work will include extensive use of imagery from a range of sources, primarily satellite-based but also airborne remote sensing, climate observations, and climate projections to derive geospatial products characterizing ecosystem properties (e.g. canopy structure, biomass, habitat heterogeneity, disturbance severity, vegetation regrowth dynamics) and conservation priorities. The work will focus on a variety of ecosystems including boreal, temperate and tropical forests. There will be opportunities to work in the following areas: 1) fusing multi-sensor imagery, geospatial datasets and field observations to map and predict ecosystem properties and change, 2) modeling species distributions and vulnerability, 3) landscape connectivity modeling and landscape pattern analysis to identify biodiversity conservation priorities, 4) software and algorithm development using Python, Google Earth Engine, R and similar open-source platforms. The ability to synthesize complex information and develop structured analyses in written and visual form is essential.

If you would like to post a position, email Support.

Published ABoVE Data

Published ABoVE data archived at ORNL DAAC have been accessed 74,639 times by a total of 14,459 unique users (identified by IP address) since January 2015. A total of 180 field, airborne, and modeled data products from ABoVE research are now available from the ORNL DAAC. In the last year, 11 ABoVE datasets have been archived at the ORNL DAAC and 12 ABoVE preprint datasets have been released to support the peer-review process for manuscripts. ABoVE datasets have been cited 149 times by other publications thus far in the campaign. Browse ABoVE data at the ORNL DAAC. As a reminder, the LVIS data collected for ABoVE are available from the NSIDC DAAC and UAVSAR data are archived at the Alaska Satellite Facility.

The three most-downloaded ABoVE datasets in calendar year 2023 are:

The three most-downloaded ABoVE datasets of all time (as of Oct. 31, 2023) are:

NASA Stories and Media Coverage

ABoVE has been getting a lot of attention in the Media and NASA's news team. Check out what has been covered!

ABoVE Jobs

Multiple job openings with ABoVE Projects. If you would like to post a position, email support@cce.nasa.gov.